A formal test of the theory of universal common ancestry

  title={A formal test of the theory of universal common ancestry},
  author={Douglas L. Theobald},
Universal common ancestry (UCA) is a central pillar of modern evolutionary theory. As first suggested by Darwin, the theory of UCA posits that all extant terrestrial organisms share a common genetic heritage, each being the genealogical descendant of a single species from the distant past. The classic evidence for UCA, although massive, is largely restricted to ‘local’ common ancestry—for example, of specific phyla rather than the entirety of life—and has yet to fully integrate the recent… 
Origins of life: Common ancestry put to the test
Douglas Theobald has framed the UCA view as a formal hypothesis and put it to the test using Bayesian statistical analysis of the sequences of universally conserved proteins and contrasting the results with alternative models where genetic similarity is not assumed to reflect phylogenetic relatedness.
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A formal, quantitative test of UCA in which model selection criteria overwhelmingly choose common ancestry over independent ancestry, based on a dataset of universally conserved proteins, demonstrates that real universally Conserved proteins are homologous, a conclusion based primarily on the specific nested patterns of correlations induced in genetically related protein sequences.
Was the universal common ancestry proved?
It is thought that the test of Theobald is not sufficient enough to reject the alternative hypothesis of the separate origins of life, despite the Akaike information criterion (AIC) of model selection giving a clear distinction between the competing hypotheses.
The common ancestry of life
A computational experiment on a concatenated alignment of universally conserved proteins shows that the purported demonstration of the universal common ancestry is a trivial consequence of significant sequence similarity between the analyzed proteins.
Statistical evidence for common ancestry: New tests of universal ancestry
The novel statistical methods presented here provide formal means to test separate ancestry versus common ancestry from aligned DNA sequence data while accounting for functional constraints that limit nucleotide base usage on a site-by-site basis.
Universal common ancestry, LUCA, and the Tree of Life: three distinct hypotheses about the evolution of life
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Statistical evidence for common ancestry: Application to primates
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Infinitely long branches and an informal test of common ancestry
It is concluded that the UCA test as originally proposed should not be trusted unless convergence has already been ruled out a priori, and a class of frequentist tests that perform better than the purportedly formal U CA test are presented.
Some Problems in Proving the Existence of the Universal Common Ancestor of Life on Earth
It is shown that the alignment gives a strong bias for the common ancestor hypothesis, and an example that Theobald's method supports a common ancestor hypotheses for two apparently unrelated families of protein-encoding sequences is provided.
Reconstructing the Last Common Ancestor: Epistemological and Empirical Challenges
It is argued that LGT poses insurmountable challenges for detailed and rich in details reconstructions and proposed a middle-ground position with the reconstruction of a slim LCA based on traits under strong pressures of Negative Natural Selection, and for the need of consilience with evidence from organismal biology and geochemistry.


Testing the hypothesis of common ancestry.
This work reviews and critically examines some arguments that have been proposed in support of the hypothesis that all life on earth traces back to a single common ancestor, and describes some theoretical results that suggest the hypothesis may be intrinsically difficult to test.
Application of phylogenetic networks in evolutionary studies.
This article reviews the terminology used for phylogenetic networks and covers both split networks and reticulate networks, how they are defined, and how they can be interpreted and outlines the beginnings of a comprehensive statistical framework for applying split network methods.
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On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for Life
Charles Darwin's seminal formulation of the theory of evolution, "On the Origin of Species" continues to be as controversial today as when it was first published. This "Penguin Classics" edition
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It is argued that for Darwin the tree of life was a hypothesis, which lateral gene transfer in prokaryotes now shows to be false, and a more general and relaxed evolutionary theory is proposed.
Testing fundamental evolutionary hypotheses.
Evolution: The Modern Synthesis
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On the Occurrence of Horizontal Gene Transfer Among an Arbitrarily Chosen Group of 26 Genes
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